Structurally, plant and animal cells are very similar because they are both eukaryotic cells. They both contain membrane-bound organelles such as the nucleus, mitochondria, endoplasmic reticulum, golgi apparatus, lysosomes, and peroxisomes.

Plant Cells, Chloroplasts, and Cell Walls. In particular, organelles called chloroplasts allow plants to capture the energy of the Sun in energy-rich molecules; cell walls allow plants to have rigid structures as varied as wood trunks and supple leaves; and vacuoles allow plant cells to change size.

Figure 26-2 Animals carry out seven essential functions: feeding, respiration, circulation, excretion, response, movement, and reproduction.

There are 7 essential functions of animals:

• Feeding: Herbivore = eats plants.
• Respiration: Take in O2 and give off CO2.
• Circulation: Very small animals rely on diffusion.
• Excretion: Primary waste product is ammonia.
• Response: Receptor cells = sound, light, external stimuli.
• Movement:
• Reproduction:

Like your own, an elephant’s body has hair, skin, bones, muscles, blood vessels, eyes and ears. It also has a stomach, heart, kidney, bladder, brain and other organs. These and other parts of your body make up your anatomy.

Animals can be classified according to different physical characteristics, such as body covering (e.g., hair, fur, feathers, scales, shells), body shape (e.g., two main features, three main features), appendages (e.g., arms, legs, wings, fins, tails), and method of movement (e.g., walking, crawling, flying, swimming).

All animals are eukaryotic, multicellular organisms, and almost all animals have specialized tissues. Most animals are motile, at least during certain life stages. Animals require a source of food to grow and develop. All animals are heterotrophic, ingesting living or dead organic matter.